Last weekend in Nashville, Tennesee, a gunman with a semi-automatic AR-15 killed four people in a Waffle House restaurant before being disarmed by a customer in the restaurant. The gunman escaped and was apprehended on Monday after a daylong manhunt.

Waffle House, an all-night restaurant, is a popular chain in the South, similar to Denny's or IHOP. "An icon throughout the Southeast, dotting interstate exits seemingly wherever you go and a favorite of barflys after last call," is how Fortune described Waffle House this month. But how many Waffle Houses are there?

So, how many Waffle Houses are there?

If you live in Northeast and have never seen one, you're excused for wondering how many Waffle Houses are there? There are 2,100 Waffle House restaurants nationwide, mostly in the Southeast, although there are Waffle Houses in 25 states. You can see a list of Waffle House locations here.

Founded in Georgia in 1955, the restaurant chain is primarily a Southern phenomenon, although as of 2017 the chain had expanded as far north as Ohio and Pennsylvania. The CEO of Waffle House is the son of the chain's founder, and the business is tightly controlled: Only 20 percent of the locations are franchises, and there is a “very long and very distinguished" waiting list to own them, the vice chairman emeritus told Atlanta magazine in 2016.

At a news conference on Sunday, Waffle House CEO Walter Ehmer thanked James Shaw, Jr., the 29-year-old customer who grabbed a gun from the Nashville shooter and wrestled it out of his hands. "I went behind a push door — a swivel door," said. "He shot through that door — I'm pretty sure he grazed my arm. At that time I made up my mind ... that he was going to have to work to kill me. When the gun jammed or whatever happened, I hit him with the swivel door."

"You don't get to meet too many heroes in life," said Ehmer to Shaw. "We are forever in your debt."

The shooter, 29-year-old Travis Reinking, was apprehended by the Nashville police on Monday afternoon.